Refrigerator door grounding arrangement



. S pt. 16. 1969 R. T. JAHR 3,467,938

REFRIGERATOR DOOR GROUNDING ARRANGEMENT Filed Sept. 11. 1967 INVENTOR.

RICHARD T JAHR BY M ATTORNEYS,

United States Patent 3,467,938 REFRIGERATOR DOOR GROUNDING ARRANGEMENT Richard T. Jahr, Minneapolis, Minn., assignor, by mesne assignments, to Franklin Manufacturing Company, St. Cloud, Minn., a corporation of Iowa Filed Sept. 11, 1967, Ser. No. 666,581 Int. Cl. H01r 39/00, 3/06; H05k 5/02 US. Cl. 339-4 4 Claims ABSTRACT OF THE DISCLOSURE A refrigerator comprising an open-sided cabinet having an outer metallic shell and a door having an outer metallic shell pivotally supported on said cabinet for closing the open side of the cabinet. Means are provided .for electrically grounding the door to the cabinet. Such grounding means includes top hinge means secured in electrical contact with the outer shell of the cabinet, the top hinge means having a pivot pin projecting downwardly there from, ground tab means secured in electrical contact with the outer shell of the door and a ground wire connected between the pivot pin and the ground tab means.

BRIEF SUMMARY OF THE INVENTION This invention relates to a refrigerator cabinet, and more particularly, to an improved refrigerator cabinet having grounding means between the cabinet and the door thereof. Refrigerators today often have electrical components such as lights, ice makers, and controls in the door thereof. Since the door is normally pivotally mounted in plastic bearings on the cabinet for maximum service life and free operation, it is isolated electrically from the cabinet. If an individual were to touch the handle of the door which has an electrical short in it and at the same time come into contact with the cabinet, it might be possible to subject such person to line voltage. Obviously, such potential safety hazard is undesirable and must be obviated.

The device includes, in a refrigerator having a hinged door and electrical components in the door with conductors extending thereto through one hinge, a grounding wire secured to the metallic shell of the door and se cured to a hinge pin which nests in an insulative bushing in the door and is part of a second hinge secured to the metallic shell of the refrigerator cabinet.

An object of the present invention is to provide a refrigerator having an open-sided cabinet closed by a door, wherein both the door and the cabinet being made from a sheet metal outer shell, with means for grounding the door to the cabinet to prevent shocking the user in the event of an electrical short in the door.

Another object of the present invention is to provide an improved refrigerator cabinet construction having grounding means between the door and the cabinet, such grounding means being inconspicuous and being easy to install in refrigerators during manufacture so as to obviate a possible hazardous condition. Other objects and advantages of the present invention will become more apparent hereinafter.

BRIEF DESCRIPTION OF THE DRAWING In the drawing there is illustrated a presently preferred embodiment of the present invention wherein like numerals refer to like elements in the different views.

FIG. 1 is a perspective view of a refrigerator embodying the present invention;

FIG. 2 is an exploded perspective view of a portion of the refrigerator cabinet illustrating the grounding means of the present invention; and

Patented Sept. 16, 1969 ICC DESCRIPTION OF THE INVENTION Referring now to the drawing, there is illustrated a refrigerator 10 having a cabinet 12 provided with an open side. The term refrigerator as used in the present specification includes not only a conventional refrigerator having a single compartment for containing product to be refrigerated, but also a refrigerator-freezer or a freezer unit for storing commestibles. The refrigerator 10 includes an insulated cabinet having an open side and a door pivotally secured to the cabinet for closing the open side. Refrigeration components are housed in the cabinet for refrigerating the interior thereof. Such components include a refrigerant compressor, condenser, expansion means and evaporator interconnected in the usual manner.

The cabinet 12 is formed of inner and outer shell 14 and 16, with at least the outer shell being made from metal. The space between the inner and outer shell is filled with a suitable insulating material, as for example, a polyurethane foam as is commonly employed today. The door 20 which is adapted to close the open side of the cabinet 12 is hinged at the top and at the bottom to the cabinet for free swinging movement. The door 20 may be similarly fabricated from inner and outer shells. The outer shell is preferably of metal. The shells of the door are spaced apart by an insulating material, and recesses may be provided in the inner liner or shell for re ceiving product to be stored and for accommodating electrical components, such as light, butter compartment controls, a heater or the like.

The door 20 may be pivotally secured to the cabinet 12 by means of upper and lower hinges. In accordance with the present invention, the upper hinge is formed in a particular manner so as to accommodate grounding means for grounding the door 20 to the cabinet 12. The upper hinge or top hinge 22 comprises a top hinge plate 24 secured at one end in electrical contact with the metal outer shell 14 of the cabinet 12 by means of bolt 26 and tapping plate 28. The tapping plate 28 is made from metal and is provided with tapped openings 29 which engage and receive the threads on the bolt 26. The hinge plate 24 is in direct contact with the outer metallic shell 14 and the tapping plate 28 is also in direct contact with the outer shell 14. To insure good electrical contact between the tapping plate 28 and the cabinet 12, the top surface of the tapping plate is serrated and the area of the outer shell flange 15 engaged by the tapping plate 28 is not painted.

Depending downwardly from the hinge plate 24 is a hinge pin or pivot pin 30 which is adapted to be received within an insulated bearing 32 disposed in an opening 34 in the door 20.

At its lower end the door 20 is pivotally supported by lower hinge means including a hinge pltae 36 having a hollow hinge pin portion 38 extending upwardly therefrom. The hinge pin portion 38 is received within an insulated bearing 40 disposed in an opening 42 in the bottom of the door 20. The hinge pins 30 and 38 are aligned with one another, and their axes are coaxial so as to define the axis of rotation of the door.

The insulated bearings 32 and 40 may be molded from a suitable plastic, for example, nylon.

The hinge pin portion 38 of the lower hinge means 36 is hollow and defined by an annular sleeve having an opening therethrough for receiving electrical wire means 44 which connect the power source in the refrigerator cabinet with electrical components in the door. Such power source may typically be volts.

Provided between the front of the cabinet and the rear of the door are suitable gasketing means 48 for providing a thermal insulating shield between the door and the cabinet. The gasketing means include complementary sealing points which extend entirely about the open side of the cabinet between the cabinet 12 and the door 20.

Considering again the arrangement for grounding the door 20 to the cabinet 12, a grounding wire 50 extends between the hinge pin 30 and a grounding tab 52 secured to the outer metal liner of the door in electrical contact therewith. Suitable means are provided for securing the ends of the grounding wire 50, which may be formed from stranded wire, to the pin 30 and the grounding tab 52. Such means may include screws 53 and 54. The grounding wire will be subject to minimum turning or twisting stress and thus will not be prone to mechanical failure.

There is provided by the present invention simplified grounding means for grounding the door to the cabinet in a refrigerator cabinet construction so as to obviate possible hazardous conditions in the event there is a short in the door, and the user contacts the door and the cabinet at the same time. Normally, the outer shell or outer case of the cabinet 12 is grounded through the electric service cord to the household electrical system. By virtue of the present invention, the door is grounded to the cabinet by means including a ground wire electrically connected at one end to the door and at the other end to a hinge pin that is in turn electrically connected to the outer metallic shell of the refrigerator cabinet. The novel arrangement makes maximum use of existing components and accomplishes the desired result in a relatively simple, inconspicuous manner so as not to mar the aesthetic appearance of the refrigerator cabinet.

I claim:

1. In a refrigerator comprising a cabinet formed with an open side and a door pivotally supported on said cabinet for closing said open side, said cabinet and said door each having a metallic shell, electric wire means extending from the cabinet into the door for connection of operative electrical components in said door to a source of electrical power in the cabinet, the improvement comprising means for grounding the refrigerating door in the event .4 of a short in the electrical wire means in the door, such grounding means comprising a hinge member secured to the cabinet in electrical contact with the metal shell of the cabinet, said hinge member including a hinge pin ex- 5 tending therefrom, said door having an opening therein in alignment with the hinge pin, and an insulated bearing in said opening for receiving said hinge pin, grounding tab means on said door in electrical contact with the said metal shell of the door and ground wire means connecting the grounding tab means to the hinge member.

2. A refrigerator as in claim 1 including a metallic tapping plate having threaded openings therein secured to the cabinet in electrical contact with the metallic shell, said hinge member including a metal plate, and bolt means extending through the metal plate and cabinet into engagement with the threaded openings in the tapping plate for securing the hinge means to the cabinet in electrical contact therewith.

3. A refrigerator as in claim 1 wherein the door is pivotally supported at its lower end by hinge means including a hollow hinge pin, the electric wire means extending from the cabinet into the door through said hollow hinge pin for providing power to the electrical components in such door.

4. A refrigerator as in claim 3 wherein the door is pivotally supported on the cabinet at each end in insulated bearings, whereby the door is electrically insulated from the cabinet except for the grounding means.

RICHARD E. MOORE, Primary Examiner US. Cl. X.R. 

